1. Field of the Invention
The invention relates to a molded polymeric header assembly for connecting an implantable medical device to a body organ assisted by the medical device. More particularly, the present invention relates in one embodiment to a method for making a header assembly in which the embedded electrical connectors are precisely located in a dense arrangement within the molded polymeric header body.
2. Prior Art
Implantable medical devices have feedthrough conductors in the form of pins or wires connected to the internal components of the medical device. The feedthrough wires extend through a wall of the medical device housing and are electrically insulated there from by a ceramic-to-metal seal or a glass-to-metal seal. Electrical continuity to a conductor lead attached to the body being assisted is established by connecting intermediate conductor wires supported by a polymeric header mounted on the medical device to the feedthrough wires of the implantable device and terminal blocks in the molded header body. The terminal blocks then provide for plugging the conductor lead into the molded polymeric header. Examples of this type of header assembly are shown in U.S. Pat. Nos. 4,254,775 to Langer, 4,262,673 to Kinney et al., 4,764,132 to Stutz, Jr., 5,282,841 to Szyszkowski and 5,336,246 to Dantanarayana. The disclosures of these U.S. patents are incorporated herein by reference.
U.S. Pat. No. 7,167,749, issued Jan. 23, 2007 to Biggs et al., which is assigned to the assignee of the present invention and incorporated herein by reference, discloses a header assembly comprising a body of polymeric material supporting at least one unitary conductor wire. The header may have multiple conductor wires. The conductor wires connect between feedthrough wires exiting the medical device and terminal blocks into which conductor leads plug.
Implantable medical devices have become more complex in recent years. In addition to providing a stimulus or other beneficial treatment to a body organ, the devices may include sensors and/or remote imaging devices which are to be connected to the circuitry within the device casing. The devices may also perform more than one medical function. Due to the growing complexity of implantable medical devices, there is a need for a header that provides a greater number of electrical connectors for leads and sensors that are connected to the device. The size of the header must be maintained approximately constant, with the electrical connectors closely spaced therein. There is thus a need for a molded polymeric header in which the electrical wires and terminal blocks are located with a high degree of precision. This is so a reliable electrical connection can be made with all of the associated feedthrough wires exiting the medical device. There is also a need for a method to connect a medical device having a complex array of feedthrough wires to a header with a correspondingly complex array of electrical conductors.